Tips for indicating drills in lathe turret?

[Cole2534]

How are you guys indicating drills in your lathe turret? I can never get them dialed as well as I'd like and this can lead to a bell mouth hole in some cases. Let's assume they're twist drills being held in ER collets, 2 axis lathe with no live tools, attempting to get all 6 bores centers on x0.

I've tried indicating the turret bore, indicating the holder's taper, indicating a pin in a collet, using the tool probe with a pin and just eyeballing it. So far, the MK1 eyeball has provided the best solution being suitably accurate and fast but this doesn't seem like best practice. My attempts with the indicator never seem to be quite right (this probably means the turret needs aligned, but it turns straight). By not right I mean the drill point doesn't meet the center of the material.

The turret has 1.5" holes, bushings to 1" for the straight shanks on ER16 and 32 holders.

The drills seem straight when rolled across the surface plate.

The end goal is to set the 6 round tool positions X0 and only change the Z0 as I swap tools. Perhaps this is unreasonable?

Thanks crew.

 

[Scruffy887]

Sweep them all and write it down. That's what I did 23 years ago for my first lathe. But 3rd lathe was last year. Guessed at the number and adjusted the program to make good parts.
But my needs are very different.

 

[sinha]

For setting X0 for a drill, one method can be to touch a known diameter from the side of the drill. The X position of the drill would be workpiece dia plus the drill dia.

 

[Orange Vise]

If the turret is misaligned, the X position of the drill tip will change depending on the length of the drill. Doesn't matter if it turns straight; that just means the Z-axis rails are aligned, and those usually stay straight even in a crash.

Sweep the turret in Z and see what you get.

 

[Cole2534]

If the turret is misaligned, the X position of the drill tip will change depending on the length of the drill. Doesn't matter if it turns straight; that just means the Z-axis rails are aligned, and those usually stay straight even in a crash.

Sweep the turret in Z and see what you get.

Could you elaborate on how to do this? Which faces are you sweeping?

I bet this has some hints. Will watch it in the AM....

 

[Fancuku]

I always bore after I drill so I never cared about indicating drills. I drill at least .05" less than the finished bore diameter.

 

[Cole2534]

I always bore after I drill so I never cared about indicating drills. I drill at least .05" less than the finished bore diameter.

Boring clearance holes sounds like a waste of time, but ok.

 

[Fancuku]

Boring clearance holes sounds like a waste of time, but ok.

We don't do any clearance holes. It's either threaded or tight tolerance hole for press fit bushings.

 

[BT Fabrication]

are you spotting the holes and using stub length drills or normal length?

 

[Cole2534]

are you spotting the holes and using stub length drills or normal length?

Spotting, then using anything between screw length and some 9" long drills.

 

[DouglasJRizzo]

If indicating the turret holders is not producing a decent "zero" in X then turret alignment and even the holders themselves should be thoroughly checked.
I swept all of mine in and they drill straight on. The Turret is dead on also, as were the holders.
Many machines have locator pins or shoulders for the turret holders, make sure these are in good shape too.

 

[Ox]

I just run floating holders.
You guys can spend your days indicating if you prefer.


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Think Snow Eh!
Ox

 

[camhead420]

I just run floating holders.
You guys can spend your days indicating if you prefer.


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Think Snow Eh!
Ox

I have used a floating reamer holder, never for a drill. Is this pretty common?

 

[Ox]

I don't think it's "common".


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Think Snow Eh!
Ox

 

[Cole2534]

If indicating the turret holders is not producing a decent "zero" in X then turret alignment and even the holders themselves should be thoroughly checked.
I swept all of mine in and they drill straight on. The Turret is dead on also, as were the holders.
Many machines have locator pins or shoulders for the turret holders, make sure these are in good shape too.

I don't think it's "common".


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Think Snow Eh!
Ox

Mind elaborating?

 

[Ox]

You have a specific question?


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Think Snow Eh!
Ox

 

[Mtndew]

I just run floating holders.
You guys can spend your days indicating if you prefer.


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Think Snow Eh!
Ox

Got a floating holder for a 3" indexable drill handy?

 

[Ox]

I have floaters that go up to 1" capacity at least, but I don't think that an insert drill is a good application for floating, nor does it need to be dead on C/L either.

I have insert drills that go to over 3", and have never used a floater on those.


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Think Snow Eh!
Ox

 

[Skubeesnak]

I have loaded a adjustable boring head in spindle then put homemade undersized tool reducing bushings in tool holders and finish bored them in the turret. you will have to have set screws that go thru the bushings on one side tool grip on 1.0 shank and tighten them on opposite side to the bushings.

 

[tay2daizzo8]

I just run floating holders.
You guys can spend your days indicating if you prefer.


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Think Snow Eh!
Ox

if you want it done right the first time just float it. 100% with Ox here